I was recently surprised to discover that, unlike brushing, flossing has not been clinically proven to prevent periodontal infections.
One of the common causes of endocarditis, it turns out, is getting a thorough tooth cleaning in a dentists office. The sharp instruments penetrating below the gum line force bacteria into the bloodstream. In immune compromised people, the infection can get out of control.When I was a kid I used to floss every day just like my dentist advised. Then I went though medical school and learned about something called endocarditis, a bacterial infection of the heart valves, which develops in people whose immune systems are unable to eradicate the invading bacteria before they can burrow into the valvular tissue.
For me, this is not merely a theoretical issue. My brother, who had a compromised immune system from a bone marrow transplant while I was in medical school, nearly lost his life when he had his teeth cleaned prior to undergoing radiation treatment.
Even in the absence of obvious infection, bacteria in the bloodstream can trigger a subclinical immune system response that may lead to inflammation in the blood vessel walls where it can contribute to atherosclerosis and other diseases associated with aging.
Like dental cleaning, flossing also forces bacteria into the bloodstream.
After my brother’s experience I reconsidered my flossing habit. Flossing removes food, but it seemed to me that shoving a string between your teeth and randomly sliding it around was unlikely to remove bacteria one thousandth the size of the string. What I decided to do instead was to focus instead on brushing right after a meal to prevent bacteria from forming the kind of biofilm that could establish between my teeth and under the gum line. Some bacterial species divide as quickly as every twenty minutes, so that was my cut-off time.
Since then, for the past twenty three years, I floss when I’ve gotten something stuck between my teeth and otherwise I’ve avoided flossing and have not had any problems.
In fact, I hadn’t even given my lack of flossing much thought until my good friend from Kauai, Will Revak, asked me to participate in his HealthyMouth Summit, which launches today and runs through this week. When Will sent me the invitation, I immediately thought of the flossing question and decided it would be a great excuse to educate myself.
I go into more detail during the summit interview, but here’s two conclusions you may find surprising:
- There’s never been any compelling research showing that daily flossing promotes better oral health or reduces gingivitis.
- Some research suggests that if you have gingivitis and you floss irregularly, you are forcing bad bacteria into your bloodstream. Daily flossing in this setting may be advantageous, interestingly enough.
- Water swishing, a less aggressive means of removing interdental debris, may be an effecive alternative.
So what should you do?
Of course I’m not a dentist, so I am not going to advise anyone to spit out the idea of flossing altogether. If you floss regularly and that working for you, that speaks for itself. Besides, if you have something stuck in your teeth, flossing is the fastest way get it out of there. But it does seem prudent that if you don’t floss and are immune suppressed for any reason, to talk to your dentist about what he or she recommends to reduce the risk of introducing significant amounts of bacteria into your bloodstream.
I found these articles balancing the risks of flossing interesting. I’m sticking to the idea that more information is almost always a good thing and invite other oral health professionals to join the conversation.
Publications that I found compelling include: